const str ='hello'//字符串
const num=12312321//只要数字，都用num
const flag =true
const u =undefined
const n=null
const s=Symbol(1)
const s2=Symbol(1)
//s和s2不相等，因为Symbol是专门用来定义唯一变量的
const b=12312312312n//有上限，后面推出bigint
const arr=['1','2','3','4','5']
const obj ={
    name:'竺梓君',
    age: 18,
    like: ['running','rap'],
    info:{
    city:'南昌',
    girlfriend: 3
    }
}